attach_user_policy · Awslabs Valkey MCP: Risk & Policy

WHAT IT DOES

What attach_user_policy does on Awslabs Valkey

AI agents use attach_user_policy to create or update resources in Awslabs Valkey — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Awslabs Valkey environment.

WHY IT NEEDS A POLICY

Why attach_user_policy needs a policy

Attaching a policy to an IAM user reversibly modifies access control and permissions. This is a Write operation (modifies data/configuration), not Destructive (the attachment can be removed). However, it carries high severity because policy attachment mistakes can grant unintended permissions or compromise security posture.

From the tool's definition Tool name 'attach_user_policy' indicates a modification operation. The sibling tools include 'add_inline_policy' and 'add_user_to_group', which are clearly Write operations that modify IAM configuration.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

attach_user_policy Rate-limited

attach_user_policy stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "attach_user_policy": {
      "limits": [
        {
          "counter": "attach_user_policy_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches Awslabs Valkey, so you can run agents against it safely.

FAQ

Questions about attach_user_policy

What does the attach_user_policy tool do? +

attach_user_policy. It is categorised as a Write tool in the Awslabs Valkey MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on attach_user_policy? +

Register the Awslabs Valkey MCP server in PolicyLayer and add a rule for attach_user_policy: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Awslabs Valkey. Nothing to install.

What risk level is attach_user_policy? +

attach_user_policy is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit attach_user_policy? +

Yes. Add a rate_limit block to the attach_user_policy rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.

How do I block attach_user_policy completely? +

Set action: deny in the PolicyLayer policy for attach_user_policy. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.

What MCP server provides attach_user_policy? +

attach_user_policy is provided by the Awslabs Valkey MCP server (awslabs.valkey-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.